cifs: fix length calculation for converted unicode readdir names

commit f12f98dba6ea1517cd7fbb912208893b9c014c15 upstream.

cifs_from_ucs2 returns the length of the converted name, including the
length of the NULL terminator. We don't want to include the NULL
terminator in the dentry name length however since that'll throw off the
hash calculation for the dentry cache.

I believe that this is the root cause of several problems that have
cropped up recently that seem to be papered over with the "noserverino"
mount option. More confirmation of that would be good, but this is
clearly a bug and it fixes at least one reproducible problem that
was reported.

This patch fixes at least this reproducer in this kernel.org bug:

    http://bugzilla.kernel.org/show_bug.cgi?id=15088#c12

Reported-by: Bjorn Tore Sund <bjorn.sund@it.uib.no>
Acked-by: Dave Kleikamp <shaggy@linux.vnet.ibm.com>
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/fs/cifs/readdir.c b/fs/cifs/readdir.c
index 01ce279f2237888e65b573f9f91a40b9c9c98f63..f55d42bbf7e86f1f1424856b67e1df62cf277967 100644 (file)
--- a/fs/cifs/readdir.c
+++ b/fs/cifs/readdir.c
@@ -666,6 +666,7 @@ static int cifs_get_name_from_search_buf(struct qstr *pqst,
                                           min(len, max_len), nlt,
                                           cifs_sb->mnt_cifs_flags &
                                                CIFS_MOUNT_MAP_SPECIAL_CHR);
+               pqst->len -= nls_nullsize(nlt);
        } else {
                pqst->name = filename;
                pqst->len = len;